76433

&String s pointing at String s1

初入Rust吧

fn main() {
    println!("hello world");
}

进行编译调试的时候就是执行 rustc main -o main
这样就可以实现获取得到最终的结果了吧，还是比较简单的讷

初入cargo

cargo 是rust 的一个包管理工具和包管理器吧，大多数的 rust 都是使用 cargo 来进行创建项目和管理项目的讷
cargo new project_name
核心需要关注的就是 Cargo.toml 吧

[package]
name = "hello_cargo"
version = "0.1.0"
edition = "2021"

[dependencies]

cargo build 和 cargo run 以及 cargo build --release 是十分关键的讷

猜数字游戏

/// 开始书写自己的一个猜数字的游戏吧
use std::io; // 引入 io 模块

fn main() {
    println!("guessing game begining...");

    let mut guess = String::new();  // 定义一个可变的字符串，后续是需要接收用户输入的，所以说是可变的吧

    io::stdin()
        .read_line(&mut guess)
        .expect("Failed to read line");

    println!("You guess: {}", guess);
}

步骤：先获取得到用户的输入输出
- 这里必须是一个可变的字符串吧，因为需要做的是进行对应的接受到用户的输入输出吧，以及读取得到命令行的输入进行赋值给可变的变量即可吧
以及这里面的细节还有
- 1. 可变变量的定义
- 2. rust 打印的格式化输出
- 3. 错误断言的兜底操作吧

但是现在的功能还是很少的，远远不是我们想要的猜数字的游戏吧
- 此时需要一个随机数的包 crate 吧，这里就是 rand: 0.8.3

use rand::Rng;
use std::cmp::Ordering;
use std::io;

fn main() {
    println!("Guess the number!");

    let secret_number = rand::thread_rng().gen_range(1..101);

    loop {
        println!("Please input your guess.");

        let mut guess = String::new();

        io::stdin()
            .read_line(&mut guess)
            .expect("Failed to read line");

        /// 进行对用户的输入进行清洗一下啊，确保正确性吧
        let guess: u32 = match guess.trim().parse() {
            Ok(num) => num,
            Err(_) => continue,
        };

        println!("You guessed: {}", guess);

        match guess.cmp(&secret_number) {
            Ordering::Less => println!("Too small!"),
            Ordering::Greater => println!("Too big!"),
            Ordering::Equal => {
                println!("You win!");
                break;
            }
        }
    }
}

Rust 通用性编程思想

变量和可变性

rust 定义的变量默认是不可变的讷，但是是可以通过添加关键字来实现对应的创建可变变量讷
- let variable = value 这就是创建的不可变的变量吧
- let mut variable = value 这就是创建的可变的变量吧
常量
- 与不可变变量类似，常量（constant）是绑定到一个常量名且不允许更改的值，但是常量和变量之间存在一些差异
- 首先，常量不允许使用 mut。常量不仅仅默认不可变，而且自始至终不可变。常量使用 const 关键字而不是 let 关键字来声明，并且值的类型必须注明
- 常量可以在任意作用域内声明，包括全局作用域，这对于代码中很多部分都需要知道一个值的情况特别有用。
  最后一个不同点是常量只能设置为常量表达式，而不能是函数调用的结果或是只能在运行时计算得到的值。

const THREE_HOURS_IN_SECONDS: u32 = 60 * 60 * 3;

数据类型

rust 的每个值都是确切的数据类型吧，该类型告诉 rust 数据是被定义成了什么数据类型，从而让rust知道如何使用该数据吧
基本数据类型：整型、浮点型、字符类型、布尔类型
核心关注的是符合数据类型：元组类型，数组类型、

控制流

fn main() {
    let number = 3;

    if number < 5 {
        println!("condition was true");
    } else {
        println!("condition was false");
    }
}

fn main() {
    loop {
        println!("again!");
    }
}

fn main() {
    let mut count = 0;
    'counting_up: loop {
        println!("count = {}", count);
        let mut remaining = 10;

        loop {
            println!("remaining = {}", remaining);
            if remaining == 9 {
                break;
            }
            if count == 2 {
                break 'counting_up;
            }
            remaining -= 1;
        }

        count += 1;
    }
    println!("End count = {}", count);
}

fn main() {
    let mut counter = 0;

    let result = loop {
        counter += 1;

        if counter == 10 {
            break counter * 2;
        }
    };

    println!("The result is {}", result);
}

fn main() {
    let mut number = 3;

    while number != 0 {
        println!("{}!", number);

        number -= 1;
    }

    println!("LIFTOFF!!!");
}

fn main() {
    let a = [10, 20, 30, 40, 50];

    for element in a {
        println!("the value is: {}", element);
    }
}

Rust 所有权

所有运行的程序都必须管理其使用计算机内存的方式。一些语言中具有垃圾回收机制，在程序运行时不断地寻找不再使用的内存；在另一些语言中，开发者必须亲自分配和释放内存。Rust 则选择了第三种方式：通过所有权系统管理内存，编译器在编译时会根据一系列的规则进行检查。在运行时，所有权系统的任何功能都不会减慢程序

&String s pointing at String s1

fn main() {
    let s1 = String::from("hello");

    let len = calculate_length(&s1);

    println!("The length of '{}' is {}.", s1, len);
}

fn calculate_length(s: &String) -> usize {
    s.len()
}

Rust 结构体

struct User {
    active: bool,
    username: String,
    email: String,
    sign_in_count: u64,
}

fn main() {
    let mut user1 = User {
        email: String::from("someone@example.com"),
        username: String::from("someusername123"),
        active: true,
        sign_in_count: 1,
    };

    user1.email = String::from("anotheremail@example.com");
}

fn build_user(email: String, username: String) -> User {
    User {
        email: email,
        username: username,
        active: true,
        sign_in_count: 1,
    }
}

struct Color(i32, i32, i32);
struct Point(i32, i32, i32);

fn main() {
    let black = Color(0, 0, 0);
    let origin = Point(0, 0, 0);
}

fn main() {
    let rect1 = (30, 50);

    println!(
        "The area of the rectangle is {} square pixels.",
        area(rect1)
    );
}

fn area(dimensions: (u32, u32)) -> u32 {
    dimensions.0 * dimensions.1
}

struct Rectangle {
    width: u32,
    height: u32,
}

fn main() {
    let rect1 = Rectangle {
        width: 30,
        height: 50,
    };

    println!(
        "The area of the rectangle is {} square pixels.",
        area(&rect1)
    );
}

fn area(rectangle: &Rectangle) -> u32 {
    rectangle.width * rectangle.height
}

/// 通过派生 trait 增加实用功能

#[derive(Debug)]
struct Rectangle {
    width: u32,
    height: u32,
}

fn main() {
    let rect1 = Rectangle {
        width: 30,
        height: 50,
    };

    println!("rect1 is {:?}", rect1);
}

impl Rectangle {
    fn width(&self) -> bool {
        self.width > 0
    }

    fn area(&self) -> u32 {
        self.width * self.height
    }

    fn can_hold(&self, other: &Rectangle) -> bool {
        self.width > other.width && self.height > other.height
    }

    fn square(size: u32) -> Rectangle {
        Rectangle {
            width: size,
            height: size,
        }
    }
}

impl Rectangle {
    fn area(&self) -> u32 {
        self.width * self.height
    }
}

impl Rectangle {
    fn can_hold(&self, other: &Rectangle) -> bool {
        self.width > other.width && self.height > other.height
    }
}

fn main() {
    let rect1 = Rectangle {
        width: 30,
        height: 50,
    };

    if rect1.width() {
        println!("The rectangle has a nonzero width; it is {}", rect1.width);
    }
}

Rust 枚举和模式匹配

enum IpAddrKind {
    V4,
    V6,
}

let four = IpAddrKind::V4;
let six = IpAddrKind::V6;


fn route(ip_type: IpAddrKind) { }

route(IpAddrKind::V4);
route(IpAddrKind::V6);



enum IpAddrKind {
    V4,
    V6,
}
struct IpAddr {
    kind: IpAddrKind,
    address: String,
}
let home = IpAddr {
    kind: IpAddrKind::V4,
    address: String::from("127.0.0.1"),
};
let loopback = IpAddr {
    kind: IpAddrKind::V6,
    address: String::from("::1"),
};

enum Coin {
    Penny,
    Nickel,
    Dime,
    Quarter,
}

fn value_in_cents(coin: Coin) -> u8 {
    match coin {
        Coin::Penny => 1,
        Coin::Nickel => 5,
        Coin::Dime => 10,
        Coin::Quarter => 25,
    }
}

fn value_in_cents(coin: Coin) -> u8 {
    match coin {
        Coin::Penny => {
            println!("Lucky penny!");
            1
        }
        Coin::Nickel => 5,
        Coin::Dime => 10,
        Coin::Quarter => 25,
    }
}

#[derive(Debug)] // 这样可以立刻看到州的名称
enum UsState {
    Alabama,
    Alaska,
    // --snip--
}

enum Coin {
    Penny,
    Nickel,
    Dime,
    Quarter(UsState),
}

fn value_in_cents(coin: Coin) -> u8 {
    match coin {
        Coin::Penny => 1,
        Coin::Nickel => 5,
        Coin::Dime => 10,
        Coin::Quarter(state) => {
            println!("State quarter from {:?}!", state);
            25
        }
    }
}

/// 我们在之前的部分中使用 Option<T> 时，是为了从 Some 中取出其内部的 T 值；我们还可以像处理 Coin 枚举那样使用 match 处理 Option<T>！只不过这回比较的不再是硬币，而是 Option<T> 的成员，但 match 表达式的工作方式保持不变
fn plus_one(x: Option<i32>) -> Option<i32> {
        match x {
            None => None,
            Some(i) => Some(i + 1),
        }
    }

    let five = Some(5);
    let six = plus_one(five);
    let none = plus_one(None);

use hello::ThreadPool;

use std::io::prelude::*;
use std::net::TcpListener;
use std::net::TcpStream;
use std::fs;
use std::thread;
use std::time::Duration;

fn main() {
    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
    let pool = ThreadPool::new(4);

    for stream in listener.incoming().take(2) {
        let stream = stream.unwrap();

        pool.execute(|| {
            handle_connection(stream);
        });
    }

    println!("Shutting down.");
}

fn handle_connection(mut stream: TcpStream) {
    let mut buffer = [0; 1024];
    stream.read(&mut buffer).unwrap();

    let get = b"GET / HTTP/1.1\r\n";
    let sleep = b"GET /sleep HTTP/1.1\r\n";

    let (status_line, filename) = if buffer.starts_with(get) {
        ("HTTP/1.1 200 OK\r\n\r\n", "hello.html")
    } else if buffer.starts_with(sleep) {
        thread::sleep(Duration::from_secs(5));
        ("HTTP/1.1 200 OK\r\n\r\n", "hello.html")
    } else {
        ("HTTP/1.1 404 NOT FOUND\r\n\r\n", "404.html")
    };

    let contents = fs::read_to_string(filename).unwrap();

    let response = format!("{}{}", status_line, contents);

    stream.write(response.as_bytes()).unwrap();
    stream.flush().unwrap();
}

use std::thread;
use std::sync::mpsc;
use std::sync::Arc;
use std::sync::Mutex;

enum Message {
    NewJob(Job),
    Terminate,
}

pub struct ThreadPool {
    workers: Vec<Worker>,
    sender: mpsc::Sender<Message>,
}

type Job = Box<dyn FnOnce() + Send + 'static>;

impl ThreadPool {
    /// 创建线程池。
    ///
    /// 线程池中线程的数量。
    ///
    /// # Panics
    ///
    /// `new` 函数在 size 为 0 时会 panic。
    pub fn new(size: usize) -> ThreadPool {
        assert!(size > 0);

        let (sender, receiver) = mpsc::channel();

        let receiver = Arc::new(Mutex::new(receiver));

        let mut workers = Vec::with_capacity(size);

        for id in 0..size {
            workers.push(Worker::new(id, Arc::clone(&receiver)));
        }

        ThreadPool {
            workers,
            sender,
        }
    }

    pub fn execute<F>(&self, f: F)
        where
            F: FnOnce() + Send + 'static
    {
        let job = Box::new(f);

        self.sender.send(Message::NewJob(job)).unwrap();
    }
}

impl Drop for ThreadPool {
    fn drop(&mut self) {
        println!("Sending terminate message to all workers.");

        for _ in &mut self.workers {
            self.sender.send(Message::Terminate).unwrap();
        }

        println!("Shutting down all workers.");

        for worker in &mut self.workers {
            println!("Shutting down worker {}", worker.id);

            if let Some(thread) = worker.thread.take() {
                thread.join().unwrap();
            }
        }
    }
}

struct Worker {
    id: usize,
    thread: Option<thread::JoinHandle<()>>,
}

impl Worker {
    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Message>>>) ->
        Worker {

        let thread = thread::spawn(move ||{
            loop {
                let message = receiver.lock().unwrap().recv().unwrap();

                match message {
                    Message::NewJob(job) => {
                        println!("Worker {} got a job; executing.", id);

                        job();
                    },
                    Message::Terminate => {
                        println!("Worker {} was told to terminate.", id);

                        break;
                    },
                }
            }
        });

        Worker {
            id,
            thread: Some(thread),
        }
    }
}

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rust

Rust

https://blog.luhanxin.com/archives/1bb0e6b6-25b0-4479-bda5-884d8e12d74b

作者

luhanxin|juwenzhang

发布于

2026-02-02

更新于